Mandy Moore & Minka Kelly Have a Makeup-Free Brunch in West Hollywood

Joined by another female friend, the pair stepped out for brunch at BLD in West Hollywood on Saturday.

"They were very low-key and sat in the center of the restaurant, pretty much unnoticed by fellow diners," an onlooker tells PEOPLE.

Both of the famous friends were dressed down – Moore wore her hair in a bun and a gray V-neck T-shirt, while Minka sported a cozy gray sweater with her hair down in waves – and "didn't have a stitch of makeup on," the source adds.